The present invention relates to a mechanical plug for pipes. Particularly, the assembly of this invention relates to a two piece mechanical plug for plugging pipe ends or other pipe portions to allow easy access to the pipeline. The plug assembly of this invention is particularly useful for temporarily sealing low-pressure pipelines. The two piece plug assembly is constructed and arranged to fit various pipe constructions, i.e., PVC, ABS, copper, etc. and various pipe diameters, i.e., 11/2, 2, 3 and 4 inch pipelines.
Various pipe plugs and assemblies, including mechanical plug assemblies, have been proposed and used in the past, however, each such assembly has drawbacks and limitations. Certain plugs used to seal pipe ends are difficult and costly to manufacture and to place in a pipe and/or to remove from the pipe after use. Some plugs may have to be cut off or out of the pipe to be removed, thereby destroying the plug itself, as well as potentially damaging the pipe. Other prior art pipe plugs are difficult to operate and lack sufficient sealing surfaces. Still others are constructed to deal with specific pipe sizes and do not allow for normal pipe diameter variations.
The mechanical plug assembly of this invention overcomes the shortcomings of prior art plug assemblies by providing an economical lightweight, reusable two piece mechanical plug for pipes that is easily inserted into and removed from pipelines or conduits. The plug assembly is constructed of plastic and rubber parts and does not utilize metallic portions which may corrode. The mechanical plug assembly is comprised of a rigid body member and a flexible sealing member which are joined and sealed in a pipeline by tuning the mating threads, of a predetermined thread configuration and design. The plug assembly is constructed and arranged so that it can be inserted and removed by hand, or with the assistance of a tool, such as a wrench. The plug also allows for easy access to the pipeline without damage to the plug itself or to the pipe end.
The mechanical plug assembly includes a molded rigid plastic body member which has a grasping or handle portion and a threaded sealing portion. The grasping portion is ergonomically designed and extends from the top surface of the body member and is comprised of a center grip and opposing thumb wings that allow for easy twisting and maneuvering of the body portion. The flexible sealing member is a cylindrical structure which is internally threaded in a generally cone shaped design which narrows from top to bottom. Importantly, a plurality of threads, of a specific design and configuration, are spaced external the rigid body member and internal the flexible sealing member for mating and sealing securement.
The flexible seal member of the plug assembly is generally circular in cross-section and has a cone shaped internal threaded portion. The seal member is preferably comprised of a sturdy flexible material such as rubber or the like. The seal portion is constructed and arranged to receive the threaded sealing portion of the rigid body portion to thereby radially expand the flexible seal member body. The seal member is comprised of a generally smooth outer surface, a cone shaped threaded inner surface and a top circumferential lip. The plurality of threads on the inner surface of the seal member are spaced at a predetermined distance to matingly receive the exterior threads of the rigid body member.
To seal a pipe, the seal member of the invention, having the rigid body member partially threaded therein, is place inside of the pipe or port end until the circumferential lip rests against the outer edge of the pipe port. The rigid body member of the plug assembly is then grasped by the center grip and thumb wings and further turned or threaded into the seal portion. As the threaded plug body is received by the seal member, the seal member expands outwardly so that its outer surface presses against the inner pipe surface, thus sealing the pipe. The body member and seal member remain enjoined by means of their mating thread structure. When desired, the plug body member can be turned out of the sealing member, thus making the pipe and/or its contents accessible by removal of the plug assembly.